The perimeter of a parallelogram is 144 cm. Find its sides if it is known that one of them is 3 dm longer than the other.

A parallelogram is a quadrangle in which opposite sides are parallel and equal to each other.

The perimeter of a parallelogram is the sum of all its sides:

P = AB + BC + CD + AD.

Since the perimeter of the parallelogram is 144 cm, and the side AB is larger than the side of the sun by 3 dm, that is, by 30 cm, then we express:

x – sides AB and BC;

х + 30 – sides ВС and АD;

x + x + 30 + x + 30 = 144;

x + x + x + x = 144 – 30 – 30;

4x = 84;

x = 84/4 = 21;

AB = CD = 21 cm;

BC = AD = 21 + 30 = 51 cm.

Answer: sides AB and CD are 21 cm, BC and AD are 51 cm.